I think this particular Topre model has all the best features of the different Realforce keyboards:
1. The all 55g weighted keys don't suffer from the annoying repeated 'a' and ';' problem that I've heard a lot of other people mention.
2. It's nice to have a light on the capslock key. I like to keep the keyboard in a standard configuration but find it annoying when I'm using an editor like vi and can't tell I've accidentally hit the capslock key until it's too late.
3. The numpad overlay is a cool idea, I often use the keypad on full-size keyboards, but like the tenkeyless more, because i can have the mouse closer to the keyboard.
4. The bright white keycaps and black lettering is easier to see in low-light. And the lettering is bigger and thicker than on the 86 series models.
It was tough to get this keyboard in the US, and I had to pay a lot for it, much more than I thought I'd ever pay for a keyboard, but I think it's totally worth it.